Horizontal, plug-flow reactors for composting organic wastes are available from various sources in the industry and are employed to compost organic wastes into humus-like material. Typically in plug-flow reactor units currently available in the industry, organic material to be composted is transferred by conveyor belt or the like to a feed compartment at the front or entrance of a tunnel reactor. When this feed compartment is filled, a hydraulically operated plate or ram pushes the contents of the feed compartment into the reactor. The hydraulic ram thereafter returns to its original position to be refilled with additional organic matter from the conveyor system. Repeated filling and pushing serves to seqwentially convey the organic matter through the reactor.
Air is injected into the organic matter within the reactor through various ducts which can be individually controlled. From start to finish, the organic matter is pushed horizontally by the ram, and aerated by this injection process. Generally in these composting reactors, apart from being longitudinally pushed by the hydraulic ram, and the injection of air into the system as desired, the organic wastes being pushed through the reactor remain substantially undisturbed throughout the process. Generally too, these "tunnel-type" reactors contain no moving parts other than the hydraulic ram system. The composted organic matter is removed at the rearward end of the reactor by conveyor or the like, and this partially composted mixture is then transported to a holding or maturation area where, after four to six weeks, it can be delumped and seived. Thereafter, the compost is stabilized and ready for use for soil conditioning and the like.
While these "tunnel-type" reactors are quite useful in accelerating the composting of organic wastes, they are inherently inefficient due to their very nature. In particular, it is imperative in accelerating the composting of organic wastes to provide sufficient aeration to enable and augment the aerobic activity of microorganisms therewithin essential for the composting process. The hydraulic ram mechanism of the "tunnel" reactor systems available in the industry tends to compact the organic matter as it pushes the same through the reactor. Such compaction substantially limits the capability of aerating the organic matter properly. Without proper aeration, the composting process is inhibited, and optimum composting cannot be achieved. It is important in optimizing the composting reaction that the bioculture within the organic matter be constantly exposed to new organic food sources. Undisturbed organic matter does not compost efficiently because the biocultures are not being moved and exposed to such new sources of food. Moreover, the use of the hydraulic ram device to progress the organic matter through the system depends upon the availability and addition of more organic matter to the system. It is conceivable that the availability of organic matter, and/or the mechanical reliability of the hydraulic ram device, could have an adverse effect on the uniformity and predictability of the movement of the material through the reactor and the resultant dwell or residence time therewithin. Obviously, varying processing temperatures, time and movement characteristics of the organic matter within the reaction system can effect the quality, uniformity and performance of the system and its end product.
Consequently, there remain problems in the industry in providing a continuous composting reaction process and system which can provide consistent and reliable performance. Heretofore, there has not been available a continuous process for accelerating the composting of organic matter, or a system which can accomplish such process, in a relatively simple, reliable and efficient manner.
In other industries, various conveyor systems have been utilized in a number of ways to unload or otherwise transfer goods from one place to another. For example, U.S. Pat. No. 4,143,760, which issued to O. Hallstrom on Mar. 13, 1979, concerns a reciprocating conveyor having a plurality of elongated slats mounted side-by-side and connected to a fluid pressure drive mechanism. The Hallstrom drive mechanism moves all of the slats from a start position in a load-conveying direction to transfer materials, and then sequentially moves the slats in the opposite direction back to their start position to prepare for another load-conveying movement.
The slat-type conveyors, as set forth in the Hallstrom U.S. Pat. No. 4,143,760, and related U.S. Pat. Nos. 4,144,963, 4,184,587 and 4,474,285, provide means for unloading trucks and similar containers, as well as generally transporting materials; however, they are not designed or are they capable of providing a plug-flow reactor structure necessary for composting organic matter and, consequently, have never been employed for such purpose heretofore. The subject invention incorporates this sequencing conveyor concept within a unique plug-flow reactor apparatus and method for composting organic matter to address the problems set forth above in providing an improved continuous composting reaction process and system.